IC (integrated circuit) packages are often marked for identification. Commonly the marks are placed on metallic surfaces of an integral heat spreader (IHS) assembled with or as a part of the IC package. The marks may be human readable, machine readable, or both, and are frequently used for tracking products throughout manufacturing. Typically however, if there is insufficient contrast between the character and/or features of a mark and the background of the surface upon which the mark has been formed, the readability of the mark is diminished.
Generally, the surfaces of integral heat spreaders are populated by small topographical features including scratches, pits, ridges and other such elevated features and/or depressions. These features may be clearly seen only by using a magnifying device, and to may be referred to as ‘microtopographical’ features. Although small, they tend to reflect and scatter light in a multitude of angles, presenting a ‘cluttered’ visual background for marks formed at a surface having such microtopographical features. As a result, marks so disposed are sometimes difficult to read and recognize, particularly for automated optoelectronic imaging systems as may be used in a high volume manufacturing environment.
The inability to accurately and reliably read identification marks or other marks on an IC package can interfere with manufacturing processes, product traceability, detection of product tampering, theft recovery, product authenticity confirmation, automated handling, inventory management, and numerous other operations throughout the lifetime of an IC device.